.container {
  margin: 20px auto 0;
  width: 500px;
  height: 400px;
  border: 2px solid #000;
  .item {
    width: 60px;
    height: 60px;
    background: rgba(36, 62, 141, 0.8);
    border-radius: 100%;
    transform: translate(0, 160px);
  }
}
.btn {
  margin: 20px auto 0;
  width: 500px;
  .btn-start,
  .btn-stop,
  .btn-pause {
    margin-top: 25px;
    display: inline-block;
    width: 100px;
    height: 50px;
    border-radius: 25px;
    text-align: center;
    line-height: 50px;
    background: rgba(235, 88, 21, 0.8);
    font-size: 20px;
    color: #fff;
  }
  .btn-start,
  .btn-pause {
    margin-left: 100px;
    background: rgba(7, 158, 228, 0.5);
  }
  .btn-pause {
    background: rgba(7, 228, 180, 0.5);
    display: none;
  }
}
